Keith Krause, Michael Williams, Ken Booth, and Richard Wyn Jones are scholars associated with the Critical Security Studies.

The Aberystwyth (Welsh) School, Copenhagen School, and Paris School are the main schools of thought.

The exercise of power by states toward each other is called power politics.

There are two main approaches of realism: classical realism that considers power politics in terms of egoism and neorealism, or structural realism, that explains power politics in terms of anarchy.

• Politics is governed by objective laws which have their root in human nature.
• The key to understanding international politics is the concept of interest defined in terms of power.
• The forms and nature of state power will vary in time, place and context but the concept of interest remains consistent.
• Universal moral principles do not guide state behavior, although this does not rule out an awareness of the moral significance of political action.
• Moral aspirations are specific to a particular nation; there is no universally agreed set of moral principles.
• The political sphere is autonomous

• States are seen as rational actors and by far the most important actors in the international system.

• The international system is anarchic; there is no international authority that can prevent the use of force between states.

• Each state cannot take its security for granted and thus, is responsible for ensuring its own survival, most notably through the nurturing of material capabilities.

• The balance of power (the formation of alliances with certain states to counter the threat of other states) is the defining mechanism that regulates the international system and explains war and peace.

theories about international politics can be developed at three levels of analysis: the individual level, the state level, and the international system level.

Self-help refers to a state’s reliance on its own capacities and resources, rather than external support, to ensure security and survival.

Offensive realism is a form of structural realism that portrays states as ‘power maximizers’, as there is no limit to their desire to control the international environment. Defensive realism is a form of structural realism that views states as ‘security maximizers’, placing the desire to avoid attack above a bid for World power.

• The knowledge structure, which influences actor’s beliefs, ideas or perceptions;

• The financial structure, which controls access to credit or investment;

• The security structure, which shapes defence and strategic issues;

• The production structure, which affects economic development and prosperity.

There are a number of sources of potential Chinese–US conflict. For example, cultural and ideological differences between ‘liberal-democratic’ USA and ‘Confucian’ China may provide the basis for growing enmity and misunderstanding. In this light, the peaceful transition from British hegemony in the nineteenth century to US global hegemony in the twentieth century was only possible because of historical, cultural and political similarities that allowed the UK to view the rise of the USA as essentially unthreatening. A conflict could also arise from divisions that already exist over issues such as Taiwan, Tibet and human rights generally, as well as over growing resource rivalry in Africa, the Middle East and elsewhere. However, others have portrayed the rise of China in a far less threatening light. Not only are China and the USA bound together by the bonds of economic interdependence (the USA is China’s main export market, and China is the USA’s most important creditor), but, as the twenty-first century progresses, these two powers may create a new form of bipolarity, which, as neorealists argue, would usher in a higher level of security and stability. The USA, furthermore, has an interest in China assuming greater global responsibilities, both to share the burden of such responsibilities and to encourage China to bandwagon rather than balance. 

The increasing influence of globalization after the end of the Cold War and a new wave of democratization in the 1990s each gave liberal theory an additional boost.

For liberalism, the security agenda in modern global politics has changed in a number of ways. These include, on the one hand, the expansion of ‘zones of peace’ in which the tensions and incipient conflicts implied by the security dilemma appear to be absent. Thus ‘security regimes’ or ‘security communities’ have developed to manage disputes and help to avoid war, a trend often associated with growing economic interdependence (linked to globalization) and the advance of democratization. On the other hand, September 11 and the wider threat of terrorism has highlighted the emergence of new security challenges that are particularly problematic because they arise from non-state actors and exploit the greater interconnectedness of the modern world. International security may, therefore, have given way to ‘global’ security.

Liberalism has three different forms:

• Republican Liberalism

• Interdependence Liberalism

• Liberal Institutionalism

Complex interdependence reflects the extent to which peoples and governments in the modern world are affected by what happens elsewhere, and particularly by the actions of their counterparts in other countries. This applies not only in the economic realm, through the advance of globalization, but is also evident in relation to a range of other issues, including climate change, development and poverty reduction, and human rights.

Liberal institutionalism is an approach to study that emphasizes the role of institutions (both formal and informal) in the realization of liberal principles and goals. Liberal institutionalism rejects a realist argument that international politics is a struggle for power in which military security issues are the top priority. In fact, the chief ‘external’ mechanism that liberals believe is needed to constrain the ambitions of sovereign states is international organizations. This reflects the ideas of what is called liberal institutionalism.

Hard power is the ability of one actor (usually but not necessarily a state) to influence another through the use of threats or rewards, typically involving military ‘sticks’ or economic ‘carrots’. Soft power is the ability to influence other actors by persuading them to follow or agree to norms and aspirations that produce the desired behavior.

Post-Positivism rejects the idea that it is possible to analyze the natural world and the social world in the same way. There is no objective view.

First, it is highly critical of seeing the state as a referent object and rather puts the emphasis on individual security. Moreover, its researchers think that states often create threats to individuals. Critical Security Studies implies “placing the experience of those men and women and communities for whom the present world order is a cause of insecurity rather than security at the center of the agenda”. Second, the Welsh School has its roots in the Gramscian and Frankfurt School tradition of critical theory. That is where its normative approach and the perception of security as emancipation come from. Thus the third distinctive characteristic of the approach is its emphasis on emancipation which is understood as removing any barriers that prevent individuals from freedom. The Welsh School believes that if people are emancipated, what they freely choose to do is peaceful. Furthermore, the School is easily distinguishable from the other approaches due to its normative-political agenda. Last, they intensify the understanding of security by viewing it as a derivative concept of politics. The security is seen as a reflection of the nature of politics.

A regional security complex is is based on four components as follows:

1. Regional boundaries, which differentiate itself from its neighbors.

2. Regional anarchical system, which consists of two or three independents states

3. Power differences among countries in the region,

4. The patterns of amity and enmity.

The most prominent critical theories in IR are as follows:

• Marxism and Neo-Marxism

• Critical Theory

• Poststructuralism/Postmodernism

• Social constructivism

The world systems theory is established on a three-level hierarchy consisting of a core, periphery, and semi-periphery areas. • The core countries, such as the developed North, dominate and exploit the peripheral countries for labor and raw materials. • The peripheral countries such as the less developed South are dependent on core countries for capital. • The semi-peripheral countries share characteristics of both core and peripheral countries. They are economically subordinate to the core but in turn take advantage of the periphery, thereby constituting a buffer between the core and the periphery. • This theory emphasizes the social structure of global inequality.